This invention relates to wastewater treatment and more particularly to an apparatus and method for recovering nutrients from a residential or small commercial wastewater stream.
Wastewater from residential or small commercial sites commonly contain nitrogen and phosphorus. In most water bodies of the United States the limiting nutrients for the prevention of eutrification is nitrogen and/or phosphorus. In addition, nitrogen in drinking water is a health hazard due to associated diseases such as methemoglobinemia and others that have been linked to nitrogen in drinking water. From an environmental and public health perspective the discharge of micro and macro nutrients from wastewater sources must be prevented and there is a need for an efficient and economical method to remove these nutrients from the waste stream.
There are many prior art devices and processes for the removal of dissolved and suspended organic solids and nutrients from wastewater. For instance, U.S. Pat. No. 5,532,894 to Ball et al. describes a method of improving the quality of septic tank effluent which includes passing the effluent through an aerobic filter and recycling the effluent back into the septic tank. U.S. Pat. No. 5,185,080 to Boyle describes a system for the treatment of nitrate-containing wastewater by periodic addition of a Pseudomonus bacteria and a milk carbon source into an underground treatment chamber. U.S. Pat. No. 4,279,753 to Nielson et al. describes a method for the treatment of municipal or industrial wastewater that includes a multiple series of alternating aerobic-anaerobic bioreactors in series. U.S. Pat. No. 6,080,314 to Rose describes a zeolite septic leach bed system that provides for the removal of the nitrogen contaminants directly from the septic tank effluent.
Most of these and the other known processes are treatment methods that utilize the aerobic decomposition process to convert organic materials to biological solids that can then be removed from the waste stream though settling or filtration. These methods do not significantly lower the concentration of most micro and macro nutrients from the wastewater stream, specifically nitrogen and phosphorus.
There remains a need for a low cost, simple and easily maintained system to treat residential or small commercial waste streams to a very high quality before reintroduction back into the environment. It would be preferable to have a simple low cost system that can efficiently prevent the discharge of micro and macro nutrients into the environment, especially as part of an onlot treatment system typically found in residential or small commercial situations.